Method and control unit for determining the probability of failure of a motor-vehicle component

Abstract

A method and control unit for determining the failure probability of a component of a motor-vehicle. Data in the form of damage-relevant influence parameters, which affect the failure probability of the component, are measured and stored during the operation of the component. To ascertain the failure probability, a collective loading is calculated as a determining influence parameter for establishing the fatigue limit of the component. To determine the collective loading as realistically as possible and therefore determine the failure probability as accurately as possible, the influence parameters may be evaluated during the operation of the component, in a control unit of the motor-vehicle for determining the failure probability.

1. A method for determining a failure probability of a component of a motor vehicle, the method comprising:
 monitoring data in the form of damage-relevant influence parameters, which affect the failure probability of the component;  
 storing the data during operation of the component; and  
 evaluating the influence parameters in a control unit of the motor vehicle to determine the failure probability during the operation of the component,  
 wherein the failure probability is determined within a scope of the evaluating of the influence parameters, by comparing a collective-damage sum, which is a measure of an accumulated loading of the component that is determined with the aid of the influence parameters, and a tolerable-damage sum of the component determined in preliminary stages of the evaluating of the influence parameters.  
 
     
     
       2. The method of  claim 1 , wherein the collective-damage sum is determined within the scope of the evaluating of the influence parameters, with the aid of a linear damage-accumulation hypothesis according to Palmgren-Miner, as a function of a collective loading which is a measure of an accumulated loading of the component that is determined using the influence parameters, and as a function of a Woehler component-part curve, which is a measure of the loading capacity of the component. 
     
     
       3. The method of  claim 2 , wherein the collective loading is calculated within the scope of the evaluating of the influence parameters, as a function of a loading-time function, which is recorded within a framework of the evaluating of the influence parameters, using the influence parameters. 
     
     
       4. The method of  claim 3 , wherein, within the scope of evaluating the influence parameters, a rainflow matrix, in which information regarding the accumulated loading of the component is stored, may be set up as a function of the loading-time function. 
     
     
       5. The method of  claim 1 , wherein the tolerable damage sum of the component is determined according to a linear damage-accumulation hypothesis of Palmgren-Miner, as a function of a Woehler component-part curve, which is determined in preliminary stages of the evaluating of the influence parameters and is a measure of the loading capacity of the component, and as a function of a tolerable loading of component parts of the component determined in the preliminary stages of the evaluating of the influence parameters. 
     
     
       6. A method for determining a failure probability of a component of a motor vehicle, the method comprising:
 monitoring data in the form of damage-relevant influence parameters, which affect the failure probability of the component;  
 storing the data during operation of the component; and  
 evaluating, during the operation of the component, the influence parameters in a control unit of the motor vehicle to determine the failure probability of the component;  
 wherein the failure probability is determined for the component which is one of: at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and a braking system of a motor vehicle.  
 
     
     
       7. A method for determining a failure probability of a component of a motor vehicle, the method comprising:
 monitoring data in the form of damage-relevant influence parameters, which affect the failure probability of the component;  
 storing the data during operation of the component; and  
 evaluating the influence parameters in a control unit of the motor vehicle to determine the failure probability during the operation of the component,  
 wherein the failure probability is determined for the component which is one of: at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and a braking system of a motor vehicle, and  
 wherein a collective-damage sum, which is a measure of an accumulated loading of the component that is determined with the aid of the influence parameters, and a tolerable-damage sum of the component determined in preliminary stages of the evaluating of the influence parameters are each determined for at least one of a joint common rail, an injector body, a housing of a high-pressure pump, and a cylinder head of the high-pressure pump.  
 
     
     
       8. A method for determining a failure probability of a component of a motor vehicle, the method comprising:
 monitoring data in the form of damage-relevant influence parameters, which affect the failure probability of the component;  
 storing the data during operation of the component; and  
 evaluating the influence parameters in a control unit of the motor vehicle to determine the failure probability during the operation of the component,  
 wherein the failure probability is determined for the component which is one of: at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and a braking system of a motor vehicle, and  
 wherein an injection pressure prevailing in the fuel-injection system is measured and stored as one of the influence parameters during operation of the fuel-injection system.  
 
     
     
       9. A control unit for controlling a motor-vehicle function implementable by at least one component, comprising:
 an arrangement to measure and store data in the form of damage-element influence parameters, which affect a failure probability of the component during operation of the component; and  
 an arrangement to evaluate the influence parameters for determining the failure probability of the component,  
 wherein the control unit includes an arrangement to determine the failure probability within a scope of the evaluating of the influence parameters, by comparing a collective-damage sum, which is a measure of an accumulated loading of the component that is determined with the aid of the influence parameters, and a tolerable-damage sum of the component determined in preliminary stages of the evaluating of the influence parameters.  
 
     
     
       10. The control unit of  claim 9 , wherein the collective-damage sum is determined within the scope of the evaluating of the influence parameters, with the aid of a linear damage-accumulation hypothesis according to Palmgren-Miner, as a function of a collective loading which is a measure of an accumulated loading of the component that is determined using the influence parameters, and as a function of a Woehier component-part curve, which is a measure of the loading capacity of the component. 
     
     
       11. The control unit of  claim 10 , wherein the collective loading is calculated within the scope of the evaluating of the influence parameters, as a function of a loading-time function, which is recorded within a framework of the evaluating of the influence parameters, using the influence parameters. 
     
     
       12. The control unit of  claim 11 , wherein, within the scope of evaluating the influence parameters, a rainflow matrix, in which information regarding the accumulated loading of the component is stored, may be set up as a function of the loading-time function. 
     
     
       13. The control unit of  claim 9 , wherein the tolerable damage sum of the component is determined according to a linear damage-accumulation hypothesis of Palmgren-Miner, as a function of a Woehler component-part curve, which is determined in preliminary stages of the evaluating of the influence parameters and is a measure of the loading capacity of the component, and as a function of a tolerable loading of component parts of the component determined in the preliminary stages of the evaluating of the influence parameters. 
     
     
       14. A control unit for controlling a motor-vehicle function implementable by at least one component, comprising:
 an arrangement to measure and store, during operation of the component, data in the form of damage-element influence parameters, which affect a failure probability of the component; and  
 an arrangement to evaluate, during operation of the component, the influence parameters for determining the failure probability of the component;  
 wherein the failure probability is determined for the component which is one of: at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and a braking system of a motor vehicle.  
 
     
     
       15. A control unit for controlling a motor-vehicle function implementable by at least one component, comprising:
 an arrangement to measure and store data in the form of damage-element influence parameters, which affect a failure probability of the component during operation of the component; and  
 an arrangement to evaluate the influence parameters for determining the failure probability of the component,  
 wherein the failure probability is determined for the component which is one of: at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and a braking system of a motor vehicle, and  
 wherein a collective-damage sum, which is a measure of an accumulated loading of the component that is determined with the aid of the influence parameters, and a tolerable-damage sum of the component determined in preliminary stages of the evaluating of the influence parameters are each determined for at least one of a joint common rail, an injector body, a housing of a high-pressure pump, and a cylinder head of the high-pressure pump.  
 
     
     
       16. A control unit for controlling a motor-vehicle function implementable by at least one component, comprising:
 an arrangement to measure and store data in the form of damage-element influence parameters, which affect a failure probability of the component during operation of the component; and  
 an arrangement to evaluate the influence parameters for determining the failure probability of the component,  
 wherein the failure probability is determined for the component which is one of: at least one of a direct-injecting fuel-injection system and a common-rail fuel-injection system of an internal combustion engine; and a braking system of a motor vehicle, and  
 wherein an injection pressure prevailing in the fuel-injection system is measured and stored as one of the influence parameters during operation of the fuel-injection system.  
 
     
     
       17. A stored computer program, the computer program, when executed by a computer, causes the computer to perform the following steps:
 monitoring data in the form of damage-relevant influence parameters, which affect the failure probability of the component;  
 storing the data during operation of the component; and  
 evaluating the influence parameters in a control unit of the motor vehicle to determine the failure probability during the operation of the component,  
 wherein the failure probability is determined within a scope of the evaluating of the influence parameters, by comparing a collective-damage sum, which is a measure of an accumulated loading of the component that is determined with the aid of the influence parameters, and a tolerable-damage sum of the component determined in preliminary stages of the evaluating of the influence parameters.